Self-sealing doors such as coach doors, trolleybus doors, train doors, isolating doors for refrigerating chambers or vehicles or aircraft doors may employ so-called plug-type doors which are designed to seal itself in the door frame by taking advantage of a pressure difference, for example between an aircraft cabin on the inside and the atmosphere around the aircraft in flying altitude on the outside. The pressurization forces the door body into the door frame which may be inversely wedge-shaped or which may include stop members at or around the door jamb that match corresponding door stop members arranged around the outer circumference of the door body. The higher pressure on the inside exerts a force onto the seating of the door body within the door frame or onto the bearing surfaces of the corresponding stop members and retains the door within the door frame, preventing the door from springing open until after release of the pressure or other active deployment of the door.
Those pressure-induced loads need to be redirected into the door frame and, subsequently, into the surrounding structures, such as the fuselage of an aircraft. Since the pressure-induced loads act substantially perpendicularly to the door body, for example from within the aircraft towards outboard of the aircraft, a conventional door structure may include bearing members in the form of rails or beams at the door jamb that may be spaced apart in different horizontal planes along the width of the door body and fixedly connected to the fuselage structure.
Document U.S. Pat. No. 5,636,814 A discloses an aircraft door structure having a clutch for an interior latch linkage of a plug-type door. The clutch is secured by an over-center mechanism to ensure that forces acting in opening direction on the latch will keep the latch at a fixed stop. Document U.S. Pat. No. 5,823,473 A discloses a latch-lock mechanism for an airplane cargo door including straight-through drive shafts rotated by a common powered drive unit, and pull-in hooks co-acting with pull-in pins affixed to the fuselage of the airplane adjacent to the sides of the cargo door opening to pull the cargo door into a closed position.